AFAIK, starvation is linked to BMI (body mass index) levels, so somebody who starts out with a higher BMI would indeed take longer to starve to death (assuming they could consume water to remain hydrated).

Heck, think about the fact that many overweight people survive for months on weight-loss diets, and lose amounts of weight that it would literally kill a thin person to lose. The fat people literally are taking longer to starve to death (although of course, the idea is to stop the slow starvation once they've got their BMI down to the desired level).

You have to remember that your brain needs glucose to survive. If you can't obtain it by dietary processes, either by direct ingestion of carbohydrates or by metabolism of protein, a portion of which converts to sugars, your brain will survive by converting bodily muscle tissue to glucose. It's not picky about the source of the protein, and the cardiac muscle is as available as any other muscle.

On a low calorie diet with sufficient carbohydrates or protein a fat person will live longer, but on a starvation diet, maybe not.

I think they can survive longer on a 'starvation diet' where some food it taking in, but not totally without food, as they have able the same reserves of protein and carbohydrates as anyone has, just more fat. Once the other 2 run out that's all folks.

So when a morbidly obese person starves to death, there won't be any fat on their corpse?

I dunno. The wikipedia article kinda suggests that you'll start breaking down muscle tissue along with fats for energy once you start starving, and that the muscle loss might kill you before you deplete your fat stores. So concivable a person with little muscle and a lot of fat could still be mildly fat when starvation finally did them in.

That bit of the article isn't very well written though, so maybe not. You'd sort of think that evolution would've stumbled upon a way to hold off on eating your organs until you'd lost the beer belly.

That bit of the article isn't very well written though, so maybe not. You'd sort of think that evolution would've stumbled upon a way to hold off on eating your organs until you'd lost the beer belly.

This would make more sense if the concept of a beer belly was older than a couple hundred years. Natural selection can't do much about wacky theoreticals; how often would any pre-civilization (read: pre-agriculture) hominid encounter a situation in which it had such a surfeit of food that it grew to become fat, then ran out of food very suddenly?

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.

I work with a guy who's my height and weighs 130. His thighs are smaller than my forearms. If the body needs to convert muscle tissue into glucose to survive, mine's got a heck of a lot more to work with.

I suspect that if he were to start packing lard onto his frame he'd be into the fat guy category well before he hit 204.

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.

I work with a guy who's my height and weighs 130. His thighs are smaller than my forearms. If the body needs to convert muscle tissue into glucose to survive, mine's got a heck of a lot more to work with.

I suspect that if he were to start packing lard onto his frame he'd be into the fat guy category well before he hit 204.

Really, 5'8 and 185 is skinny? I'm 6'0 and I weigh around 207 or so and I'm a fatass. Though I guess maybe that means I have no muscle.

I think they can survive longer on a 'starvation diet' where some food it taking in, but not totally without food, as they have able the same reserves of protein and carbohydrates as anyone has, just more fat. Once the other 2 run out that's all folks.

That's incorrect. There's an evolutionary reason why people get fat when they eat excess food - they're storing energy which they can burn later.

I'm 5'8, 265. Multiple body fat percentage tests show that if the liposuction fairies came in the night and removed all of my body fat I'd be 5'8 and 185. If they stopped at 10%, I'd be 5'8 and 204. This clearly puts me into the fat people category, but I'm not sure where between 204 and 185 I'd become a skinny person.

You wouldn't be skinny. You'd be muscular. You get a big workout every day from carrying around all that extra weight.

I don't think zero body fat is something anyone gets to. I saw a documentary a few years ago about a body builder for those posing shows. He would get to 2-3% fat coming up to a show by pretty much only eating tins of tuna, and he looked creepy.

The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.

I don't think gluconeogenesis works on fats. You can metabolize fat to ketones and use ketones for energy, but the brain demands glucose. On an all fat diet you'll constantly be losing muscle mass as you convert muscle to glucose to survive.

The body has enzymes that can convert fats to carbohydrates and vice versa, so assuming someone is otherwise healthy, they can't really run out of carbohydrates as long as they have body fat.

Without sidetracking the thread too much into a discussion of metabolism, I don't think it is correct to imply that fats are substrates for gluconeogenesis in humans.

In short, for the most part carbohydrates to fats is an unfortunate one-way street in people. From an energy standpoint, this is an issue mostly for the brain, which really really likes glucose for its energy substrate.

To the OP:
A person with significant fat stores would last longer, on average, than a person without them. There are other factors at play. An ideal candidate would be a fairly healthy fat guy with plenty of muscle.

This would make more sense if the concept of a beer belly was older than a couple hundred years. Natural selection can't do much about wacky theoreticals; how often would any pre-civilization (read: pre-agriculture) hominid encounter a situation in which it had such a surfeit of food that it grew to become fat, then ran out of food very suddenly?

It's older than a couple of hundred years; the word "paunch" has medieval origins going back to Latin. As long as people have had access to carb-rich diets (and especially alcohol), they've had the human equivalent of camel humps.

I've never read anything to indicate that larger people (whether or not their mass is fat or muscle) don't survive longer in general when it comes to starvation or harsh conditions. This is probably the reason research has showed that 'overweight' people live longer, on average, than those in the 'ideal' BMI range - if they have the misfortune to become terminally ill or injured, they have an advantage in having more bodily stores.

Keep in mind that death from starvation and malnutrition are not the same. Fat people could easily die from various forms of malnutrition and deficiences while still maintaning high body fat.

However, excess body fat is a disorder of the metabolism, nothing to do with storing surplus energy for famine. Species do not become fat when there is a food surplus (although they become fat for other reasons governed by hormonal balance, such as hibernation), they multiply. Unless the food they are eating promotes the metabolic changes that lead to obesity, as is the problem with our unnatural (in terms of the human animal for the majority of our evolution) modern diet, and was a persistant problem with zoo animals (leading to the common modern human problems such as obesity, heart disease, diabetes, and infertility) until an effort was made to provide each with a diet that closely mimics what they eat in their natural habitat.

I have a BMI of 16 with a normal body fat percentage (19%). Obviously I would be 'fat', not in terms of BMI but in body fat percentage, at a much lower total poundage than the vast majority of people. I am sure I would die much more quickly in the absence of food than average size or large people, as well, since I have so little total soft tissue to live off of, as well as having a very high requirement for daily calories to maintain my current weight (2200 to 3200 daily, and I'm only moderately active).

Actually, rubarbarbin, it's not true that fat people live longer on average than thinner people. Thinner people live longer, although it's not a large difference. It's only a few months longer lifespan on average.

The reason is that there are advantages going both ways. Carrying around extra weight is not good for the heart, so most of the advantage there is to thinner people. For some other causes of death though, there is some advantage to being heavier. On balance, it's better not to be overweight.

New Scientist has an aside about it this week. They said that the limiting factor is actually the amount of available b vitamins. On a water and and vitamin diet, you could live 'til the body fat runs out. But without b vitamins, the body fat can't be converted.

So when a morbidly obese person starves to death, there won't be any fat on their corpse?

With just water and literally zero food the physical stress of pure starvation can easily kill a significantly obese person well before all fat stores are completely used up. If you have some minor amount of food it's easier to glide down to near zero fat like concentration camp survivors.

That's incorrect. There's an evolutionary reason why people get fat when they eat excess food - they're storing energy which they can burn later.

See above, protein is required to manufacture carbs from fat, eating nothing means the body will cannibalize itself to get enough carbs, so a fat person will not survive longer. But if there is some food such as insects, then the person should have enough dietary protein to prevent cannibalization - which is a advantage for a fat person.

Actually, rubarbarbin, it's not true that fat people live longer on average than thinner people. Thinner people live longer, although it's not a large difference. It's only a few months longer lifespan on average.

The reason is that there are advantages going both ways. Carrying around extra weight is not good for the heart, so most of the advantage there is to thinner people. For some other causes of death though, there is some advantage to being heavier. On balance, it's better not to be overweight.

Being overweight by less than 30 pounds reduces lifespan on average by a few months. Being overweight by 30 pounds or somewhat more reduces lifespan on average by about a year. Being overweight by 80 pounds or so reduces lifespan average by at least three years. The more you're overweight by more than 80 pounds, the shorter the average lifespan you can expect.

Yes it does, as long as they can drink water. As noted by other posters, being fat doesn't provide any protection against dying of thirst.

Moreover, you can't assume that, say, having a BMI twice as high as another person means you'd take twice as long to starve to death. Fat reserves do provide important energy resources for survival when calories are scarce (that's why we evolved the ability to accumulate fat reserves, after all), but AFAIK there's no simple equation along the lines of X pounds of extra fat will allow you to go Y extra days without food.

See above, protein is required to manufacture carbs from fat, eating nothing means the body will cannibalize itself to get enough carbs, so a fat person will not survive longer. But if there is some food such as insects, then the person should have enough dietary protein to prevent cannibalization - which is a advantage for a fat person.

According to Wikipedia, the position of a camel's fatty tissue in the hump minimizes the amount of heat that a more generally-spread subcutaneous layer of fat would trap in the body, thus keeping the animal cooler. This among other adaptations like blood-cell shape and better conservation of liquid in the respiration and digestive processes.

Answer: "Yes" it takes a fat person longer to starve to death, but fat does not provide everything the body needs metabolically, and starvation puts huge stresses on the body, so a fat person that has nothing at all to eat will last longer than a less fat person, but will likely die well before all their fat reserves are completely used up.

Answer: "Yes" it takes a fat person longer to starve to death, but fat does not provide everything the body needs metabolically, and starvation puts huge stresses on the body, so a fat person that has nothing at all to eat will last longer than a less fat person, but will likely die well before all their fat reserves are completely used up.

It seems that in actual starvation diet situations like prisoners of war, concentration camps, forced labor without adequate nutrition, that obese people do survive longer than people who were already slender. That saying about 'the fat guys get skinny and the skinny guys die!' holds true. The body does adapt to consuming fat stores after an initial brief period where it consumes muscle. If it did not do this, then death from starvation would be more rapid than has been documented. Once the fat has been consumed, then of course it will continue consuming muscle until death occurs. I don't recall seeing any obese subjects in Somalia, Ethiopia or for that matter, anywhere in the world where there is famine or people being starved in concentration camps. If they were heavy at the start, they are not heavy anymore at the end!

ST's vBulletin 3 Responsive Styles

Our newly refreshed styles in 2017, brings the old vb3 to the new level, responsive and modern feel. It comes with 3 colors with or without sidebar, fixed sized or fluid. Default vbulletin 3 style made responsive also available in the pack.
Purchase Our Style Pack Now